Beverage Dispense Taps [BDTs] with a slidable sealed piston valve or a spring-loaded tensioned sealed piston valve are commonly known. The handle for opening and closing the flow through the BDT is usually attached to the tap body so that the handle movement communicates a cam surface with the piston valve to move the piston valve from the closed position to the open position. When the piston valve is in the closed position a seal is engaged to ensure no pressurised liquid can flow through the BDT. When the handle is actuated to the open position the seal is disengaged from its seat to allow liquid to flow around the piston valve and through the outlet port of the BDT into the glass. The handle moves the piston valve from the closed to open position creating a liquid conduit between the beverage inlet and the beverage outlet. In these designs there is no diffusion of the liquid flow as the BDT opens. The liquid is pressurised at the specific dispense pressure when the BDT is in the closed position and immediately de-pressurised as the BDT handle is moved to the open position. When the BDT is opened there is a rapid drop in pressure which can lead to excessive fobbing and subsequently waste beer. In such BDTs the handle can be located vertically or horizontally and similarly in alignment with the actuated directional movement of the piston valve.
In BDTs that dispense pressurised carbonated liquids, it is preferable to have a means of adjustment to control the velocity of the liquid flow through the BDT to ensure that the beverage is dispensed at a preferred flow rate. The preferred flow rate is determined as that which is suitable for producing a pre-defined final presentation of the beverage in the glass in relation to pouring speed and appearance, particularly in relation to the formation of the frothy head on the top of the beverage. The need for adjustment is due to the physical variables within pressurised dispense systems, particularly the following;                the relative volume of gas to liquid in the beverage,        the temperature variations in the system affecting the carbonation of the beverage,        the dispense pressure applied to the beverage container,        the distance of the supply line and the vertical elevation from the beverage container to the BDT,        the atmospheric pressure at the system location.        
All pressurised carbonated beverage dispense systems require equilibrium of pressure to be maintained between the container and the BDT to ensure the achievement of a suitable final presentation of the beverage in the glass. It is commonly known that the most suitable means of adjusting the liquid flow at the BDT is by means of a needle taper valve which incorporates a male taper needle valve with externally accessible adjustment means, the male taper being aligned within a female taper body having a matching taper form, that creates a parallel annular gap between the male and female tapers as the male is adjusted. When the male taper is fully inserted into the female taper the annular gap is either nil, so that the tapers form a surface seal or that the gap between the tapers is diminutive so as to restrict liquid from flowing through the valve. In this position the restriction between the two tapers is at its highest and the liquid flow rate is stopped or at its slowest. Likewise when the male taper is extended outward from the female taper the annular gap between the tapers increases, creating an increase in volume between the tapers, reducing the restriction and allowing the liquid flow rate to increase in a proportionate ratio to the dispense pressure propelling the liquid. In this position the gap between the two tapers is at the highest and the liquid flow rate is increased.
The needle taper valves currently in use to control flow rates are located in close proximity to the BDT, ideally attached to the inlet portion of the BDT or as an integral component of the BDT construction. In these constructions the means to adjust the needle taper valve is independent to the actuation of the tap handle and the opening and closing of the BDT. The operation of the BDT to pour the beverage can involve three physical actions, firstly the opening of the BDT through the movement of the handle, secondly the adjustment of the flow rate through the independent needle taper valve and thirdly the closing of the BDT through the return movement of the handle. This action is required whilst the operator of the tap also holds the glass into which the beverage is pouring.
In the current market for dispensing carbonated beverages, particularly draught beer, there is an increasing desire to dispense at faster pouring speeds to ensure maximum revenue can be achieved in limited peak drinking periods. The method of pouring fast requires experienced bar staff operators as the faster the flow the more difficult it is to control the gas breakout during the pour, leading to high levels of waste beer due to excessive head formation creating fobbing in the glass. The market need to pour faster is exacerbated by the lack of trained bar staff and the high turnover of staff in this service provision. In such instances the existing BDTs and their method of operation do not adequately meet the changing market needs and this invention is proposed as an alternative solution.
It is an object of the present invention to provide a novel Beverage Dispense Valve that when used to dispense pressurised carbonated beverages reduces or eliminates the problems described herein by providing a reliable, user-friendly BDT which is convenient to the changing market needs of faster pouring and lack of operator skills to ensure that pressurised carbonated beverages can be poured successfully at faster pouring speeds without excessive fobbing waste and without specialised operator training.
U.S. Pat. No. 6,478,200 B1 Davis describes a beverage dispense device comprising:                1. a valve body,        2. a nozzle or spout,        3. a valve comprising a valve seat and a closure member, the valve being opened and closed by movement of the closure member out of and into contact with the valve seat to allow or prevent flow of the beverage into a conically shaped flow passage way within the body,        4. a flow regulator between the valve seat and the nozzle, the flow regulator being adjustable to control flow rate through the nozzle and being in the form of a core member moveable in the conically-shaped flow passageway downstream of the valve seat and spaced from the valve seat, the core member and the flow passageway having matching tapering surfaces, and        5. the nozzle or spout being formed as an integral unit with the core and moveable upwardly and downwardly within an annular extension which depends downwardly of the valve body, the nozzle or spout sealingly engaging the inner wall of the extension by means of an annular seal which is held in a corresponding groove in the surface of the nozzle or spout. The annular seal is below ports which penetrate through the wall thickness of the flow regulator to allow beverage to flow to an outlet defined through the nozzle or spout. Therefore the annular seal is to prevent leakage of beverage and does not prevent its flow to the outlet.        
In the embodiment as described and illustrated, the closure member of the valve is an armature which is operated by a solenoid to cause it to move upwardly (upstream) out of contact with the valve seat and (downwardly) downstream into contact with the valve seat. The core member of the flow regulator below (downstream of) the valve seat is adjustable upwardly or downwardly within the flow passageway by separate screw-threaded means. The text suggests that in an alternative embodiment the adjustment may be by means of a stepper motor, for example, and where a stepper motor is used for this purpose it may have the dual function of opening and closing the valve. Another part of the text suggests that the adjustment means for the flow regulator may be a stepper motor and the valve seat may be achieved by direct contact between the core and the wall of the flow passageway. However there is no description or drawing to show how this could work in practice The valve closure member and the flow regulator are two separate components with different movements. Furthermore the description at column 1 lines 60-63 emphasises that the flow regulator is downstream of the valve and effectively provides a back pressure to the beverage being dispensed and thereby provides an adjustable pressure drop to which the beverage is subjected when the valve is opened. There is no description to explain how the core of the flow regulator could be downstream of the valve and yet simultaneously be achieving the valve seat by contact with the wall of the flow passageway.
GB 1,486,245 Leroy describes a valve member that is moveable along with a frusto-conical core member to permit both variation of the restrictor passage and opening/closing of the faucet with a single actuator. The valve member is located at the upstream end of the frusto-conical core member and comprises an annular shoulder on the core member positioned to mate with a similar shoulder on the annular valve seat at the inlet end of the chamber. An O-ring is placed on the core member shoulder to assure a pressure seal in the off position of the valve. However the valve opening is reported to serve as a “pinch point” which causes the liquid to froth immediately downstream of it. Furthermore, the liquid flow is re-directed through many planes in a constrained chamber area in order to exit the spout. The re-direction of flow of liquid through so many planes in a constrained chamber area creates turbulence and can lead to cleaning difficulties.
U.S. Pat. No. 5,244,117 Lombardo discloses a single actuator dispenser valve wherein a frusto-conical core member has a rounded tip that seals the inlet opening at the narrow end of the frusto-conical valve chamber when the valve is closed. However this arrangement also places the valve upstream of the diffusing passage between the core member and the wall of the flow passageway.
In each of the previously cited patents the flow regulator is positioned downstream of the main valve seal. In practice this configuration does not effectively regulate the flow as the positioning of the regulator must be before the valve seal to ensure that the regulator can maintain an effective back pressure in the carbonated beverage to ensure that the carbonated beverage retains its pressurised characteristics prior to the egress at the valve seal where the carbonation is allowed to break out naturally to an atmospheric conduit or nozzle and into the beverage container.
U.S. Pat. No. 5,538,028 Lombardo describes a valve which includes a frusto-conical valve member disposed in a similarly configured frusto-conical chamber section to both define a restrictive diffusing flow path when the valve is open and the sole pressure seal when the valve is closed. The pressure seal is created along a substantial length of the core member which is preferably made of resiliently compressible plastic to enhance the seal. However this arrangement involves a risk of leakage of beverage past the seal. Furthermore, baffles are used in the outlet spout to control eddying. Eddying is a turbulent condition created by the multi-directional flow path in which the liquid has to flow at the larger end of the conical taper, in that liquid entering the concave annular recess is directed into a vortex by the nature in which it has to flow around this annular recess to exit at the lower portion into the spout. Thus the flow rate is not equalised in this arrangement as the velocity of flow is greater at the lowest point of the frusto-conical concave annular recess, where the spout is positioned, whereas the flow at the highest point is decelerated, as it is required to flow around this concave annular recess before exiting into the spout.
It is an object of the present invention to provide a dispense tap having a combined valve and flow control with the flow control upstream of the valve. It is also an object of the invention to provide a device having a practical arrangement for operating both the valve and the flow regulator with a single control.